Superheterodyne receiver for very short waves



K. SHKNOL, ,ETAL 2,505,251

SU-PERHETERODYNE RECEIVER FOR VERY SHORT WAVES Filed May 9, 1946 April 25,1950

14 1 J11 d ////1 E 5 JIMXWILIAANJULIUJOTTOJWUIZ ALBERT ma me 2151 Komwlsmzm oz ADEZBHT ZUV WEEZ IN VEN TORS AT T 013M51 Patented Apr. 25, 1950 soecnncrcnonrns REGEIVER; FOR VERY. snoar waves Kornelis Swicn Knol, MaximiliaanJulius Otto Strutt lAldert-vanider Ziel, and Adelbert van. Weel, Eindhoven, Netherlands, assi'gnors, by mesneiassigmnents, to Hartford National Bank and Trust Company,

trustee Hartford, Conn., as

Application May 9, 1946, Serial No. 668,538 In the Netherlands July 30, 1941 Section 1; Public-Law 690, AugustS, 1946 Patentexpires July 30,1961

Claims; ,7 (Cl. 2511-9-20?) q This invention relates to 'a superheterodyne-reoscillations aresuppliedin phase and the received' oscillations are supplicd-in'pnsh pull to the mixing tube via a tiinagble lecher wiresystern;

'I'h'einvention will-be explained more fully by reference to the accompanying drawing in which:

Figure 1 isa schematic diagram of circuit arrangement of theabove type,

Figure 21s a schematic diagram-of a circuit arrangement according to the invention,

- Figure 3 is a diagramshowing potential distribution in the circuit of Figure 2,

' Figure'isa schematic diagram of a second circuit arrangement according to-the invention, and

Figure 5: is a schematicy diagram of a third circuit arrangement according to the invention.-

A receiver circuit arrangement of" the above" type is shown diagrammatically in Fig: l otthe' accompanying drawing; The oscillations receivedby a dipole aerial. i, 2 are supplied'totwcsupplies the local oscillations. The received". high-frequency "oscillations are consequently fed in push-pull and the local. oscillations are fed:

in phase to the'mixingtube 8;

In this circuit the two lecher-wires 3 and t willrjointly have. a high-frequency. voltage; .relatively to earth; havingthe frequency oiltheglocal oscillations, as a resultpoiwhicli.theundesired efiect occurs that the aerial system i; 2' emits the local oscillations.

According to the invention, this drawback is obviated by the oscillatorysystenr constitutedby the two leaner-wires together relatively to the surroundings having such. an electrical length that atthe place of the aerial, terminal a. potentializnode: for the local oscillations occursu Fig. 2.1shows one EIIlbOdlII'lfiIlt-Ofi-thfi invention ini'which the-IeCher-vvireS 3 i and A are elongated by:-parts I l and i2 and'the extremities arezcon nected-by -an..earthed short-circuit: bridge; it; the extension being chosen oi such: length thatthe stationary wave of the frequency of the local The conductors osci1lations;.. which occurs in the wires 3', H and i,- l2:ftogether; exhibits not? only a. potential node at thezextremity but-xalso one at'the connecting pointsrrof the: aerial i512 withtheconductors-S; 42 Underthese conditions the aerial l; 2* does'not emit the local oscillations;

Fig. .31 showsrth'evariation in potential of" the stationary wave. In: point I 3; .whichicorresponds to: the earthedzconnection between the two' con ductors: l land 52;..a potential norle occurs: The electrical length. or. the: conductors" between the: points i; 2 and; i 3 is: soz 'chosen' that? also-in. point i; 2; Where the aerialiss connected; a; potential? riodeoccurs'. i

If desired: the-r lengtln of? thexwiresa i landf I29. may also be: shorter than; in the case shown if v a preferably variable: condenser is connectedi bet-- tween.;the..shortecircuit bridge I 3: andiearth. The: desiredipotential node: atzthe point of theaerial: connection; may then be obtained by adjusting: this condenser 'toraisuitablewa'lue;

Fig: 4&showsaan.=.embodiment of the-invention: which utilises: this circuit. In' addition, the; lecher-wh'eesystem. l i, 4; i2'is surrounded by a-screeningz Hi; of. wliichxthe extremity which is? remote from: the, mixihgtube. 8: is' earthed; The: short'-circuitihridge. E3: of the. elongatedilechere wire systema is; not earthed" directly; but via. as. variable." condenser ll. By adjusting the: con-- denser. I11? to the": correct value it may be one sured: that: at: the: point: of the aerial connection a potential: node'ior the local oscillations oc.--

Fig:..5' shows anrembodiment oi'tlie invention ingwhich the lecherewiresi Brand 4, as before; are

elongatedhythe: conductors I land, 52, a screen-:-

A tuningof the ing it: surrounding these wires. oscillatory system 1 constitutedby the two lechers wires. together relatively to thescreening; which.

tuningiis such-that? at -..the'pointof the aerialconnectioma potential nodeof the local oscillations.

occnrsfis obtained: by an earthed short-circuit: bridge; 5 ll: which? connects; thescreening; M to the; twovwires H1 and. 5 Land. isrslidablealong-theirs! side ofgtheiscreening iii-and along the-two lecher.

wires-l l and} 2;:

Weolaim: Y

1.:Areeeiver; mixing-circuit forvery short,

meet. one, of. saidterminals... to a, corresponding, element of each of said systems, a transmission line-having. two conductors rneans. to. connect I each of: said conductors respe c ,tiv e ly v tofthe other,

elements of said systems, means to short circuit said transmission line at a given point thereof to produce on said line a first voltage node of said local oscillations at said short circuit means and a second voltage node of said local oscillations at a point intermediate to said given point and said other elements of said systems, means to couple the other terminal of said local oscillator to said shorting means, an antenna system to receive desired signals, bridge means positioned intermediate to said short circuiting means and the other elements of said systems to tune the transmission line to the frequency of said desired signals, and means to connect said antenna system to said second point of voltage node of said local oscillations on said transmission line between said bridge means and said systems.

2. A receiver mixing ,circuit for very short Waves, comprising a pair of electron discharge systems each having a cathode element and an anode electrode, a source of local oscillations having-two terminals, means to connect one of said terminals to the cathode elements of said discharge systems, a transmission line having two conductors, means to connect each of said conductors respectively to the anodes of said discharge systems, means to short circuit said transmission line at a given point thereof to produce on said line a first voltage node of said local oscillations at said short circuit means and a second voltage node of said local oscillations at a point intermediate to said given point and said anodes, means to couple the other terminal of said local oscillator to said shorting means, an antenna system to receive desired signals, bridge means positioned intermediate to said short circuiting means and said anodes to tune the transmission line to the frequency of said desired signals, and means to connect said antenna system to said second point of voltage node of said local oscillations on said transmission line between said bridge means and said anodes.

3. A receiver mixing circuit for very short waves, comprising a pair of unidirectional current carrying systems each having a cathode element and an anode element, a source of local oscillations having two terminals, means to connect one of said terminals to a corresponding element of each of said systems, a transmission line having two conductors, means to connect each of said conductors respectively to the other elements of said systems, means to short circuit said transmission line at a given point thereof to produce on said line a first voltage node of said local oscillations at said short circuit means and a second voltage node of said local oscillations at a point intermediate to said given point and said other elements of said systems, a conductive screen surrounding said transmission line and having one end thereof adjacent to said shorting means, means to couple said shorting means to the adjacent end of said screen, means to couple the other terminal of said local oscillator to said end' of said screen, an antenna system to receive desired signals, bridge means positioned intermediate to said short circuiting means and the other elements of said systems to tune the transmission line to the frequency of said desired signals, and means to connect said antenna system to said second point of voltage node of said local oscillations on said transmission line betweensaid bridge means and said systems.

4. 'A receiver mixing circuit for very short waves, comprising a pair ofunidirectional ourrent carrying systems each having a cathode element and an anode element, a source of local oscillations having two terminals, means to connect one of said terminals to a corresponding element of each of said systems, a transmission line having two conductors, means to connect each of said conductors respectively to the other elements of said systems, means to short circuit said transmission line at a given point thereof to produce on said line a first voltage node of said local oscillations at said'short circuit means and a second voltage node of said local oscillations at a point intermediate to said given point and said other elements of said systems, a conductive screen surrounding said transmission line and having one end thereof adjacent to said shorting means, a variable capacitor coupled between said shorting means and the adjacent end of said screen, means to couple the other terminal of said local oscillator to said end of said screen, an antenna system to receive desired signals, bridge means positioned intermediate to said short circuiting means and the other elements of said systems to tune the transmission line to the frequency of said desired signals, and means to connect said antenna system to said second point of voltage node of said local oscillations on said transmission line between said bridge means and said systems.

5. A receiver mixing circuit for very short waves, comprising a pair of unidirectional current carrying systems each having a cathode element and an anode element, a source of local oscillations having two terminals, means to connect one of said terminals to a corresponding element of each of said systems, a transmission line having two conductors, means to connect each of said conductors respectively to the other elements of said systems, a conductive screen surrounding said transmission line, first movable bridge means to short circuit said transmission line and said screen at a given point thereof to produce on said line a first voltage node of said local oscillations at said first bridge means and a second voltage node of said local oscillations at a point intermediate to said given point and said other elements of said systems, means to couple the other terminal of said local oscillator to said first bridge means, an antenna system to receive desired signals, second movable bridge means positioned intermediate to said first bridge means and the other elements of said systems to tune the transmission line to the frequency of said desired signals, and means to connect said an tenna system to said second point of voltage node of said local oscillations on said transmission line between said second bridge means and said systems.

KORNELIS SWIER KNOL. MAXIMILIAAN JULIUS OTTO STRUTT. ALDERT VAN DER ZIEL. ADELBERT VAN WEEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

